I have a R5A15 install with a Nova-T which suddenly stopped working last night. I re-ran mythtv-setup and scanned for the channels again and everything seemed hunky dory. Unfortunately, it's happened again tonight.

dmesg gives me

saa7146: found saa7146 @ mem d14b2000 (revision 1, irq 16) (0x13c2,0x1005).
DVB: registering new adapter (TT-Budget/WinTV-NOVA-T PCI).
adapter has MAC addr = 00:d0:5c:21:2f:b5
DVB: registering frontend 0 (LSI L64781 DVB-T)...

I can scan for channels quite happily using the linuxtv scan utility.

When trying to watch live tv, or record I get the following error in mythbackend.log

DVB#0 ERROR - Opening DVB frontend device failed.
(6) No such device or address

Any ideas?